Operator controlled coin collecting and refunding means for dial telephone systems



June 1951 F. R. LAMBERTY 2,558,571

OPERATOR CONTROLLED COIN COLLECTING AND REFUNDING MEANS FOR DIALTELEPHONE SYSTEMS Filed Oct. 27, 1948 6 Sheets-Sheet 1 I INVEJVTOR ByFIR.LAMBRTY' ATTORNEY June 26, 1951 F. R. LAMBERTY 2,553,571

OPERATOR CONTROLLED COIN COLLECTING. AND REFUNDING MEANS FOR DIAL TELEPHONE SYSTEMS 6 Sheets-Sheet 2 Filed Oct. 2'7, 1948 lNl/ENTOR f. R.LAMBERT) ATTORNEY June 26, 1951 LAMBERTY 2,558,571

OPERATOR CONTROLLED COIN COLLECTING AND REFUNDING MEANS FOR DIALTELEPHONE SYSTEMS Filed Oct. 27, 1948 6 Sheets-Sheet I:

5 Q1 NNL V R m5 T B N M MA W L R F IMIE Li ATTORNEY June 26, 1951 F:LAMBERTY 2,558 57 OPERATOR CONTROLLED COIN COLLECTING AND REFUNDINGMEANS FOR DIAL TELEPHONE SYSTEMS Filed 001;. 27, 1948 6 Sheets-Sheet 4com CONTROL SIDE c/ncu/r i *I Fla 4 MARC/Nab- T l T2 L R;

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JNVE/VTOR By ERLAMBERTV ATTORNEY June 1951 v F. R. LAMBERTY 2,553,571

OPERATOR CONTROLLED com COLLECTING AND REFUNDING MEANS FOR DIAL;TELEPHONE SYSTEMS Filed Oct. 27, 1948 6 Sheets-Sheet 5 INC OMING TRUNKC [RC U! T I T I INC OM/NG TRUNK C [RC U! T 1 F2 ATTORNEY 6 She ts-Sheet6 m Qk @ 20581 mokwmwmo lo l F. R'. LAMBERTY.

MEANS FOR DIAL TELEPHONE-SYSTEMS 1951 OPERATOR CONTROLLED COINCOLLECTING AND'REFUNDING June 26,

Filed Oct. 27, 1948 has $53 SE28 3% IN VENTOR F. R. LAMBERT) ATTORNEVPatented June 26, 1951 UNITED STATES OFFICE OPERATOR CONTROLLED COINCOLLECT- ING AND REFUNDING MEANS FOR DIAL TELEPHONE SYSTEMS ApplicationOctober 27, 1948, Serial No. 56,854

Claims.

This invention relates to communication systems and particularly tosignaling in telephone systems comprising coin subscribers stations.

Objects of the invention are the provision of improved facilities forcoin control signaling between operator positions and coin subscriberlines in automatic local telephone oliices and an increased efficiencyin the use of signaling channels between manual and automatic telephoneoffices.

The invention is an improvement in signaling between an operatorposition in a toll ofiice and a dial local office in which a compositesignaling channel is arranged for use by the operator in controlling thecollection or refund of coins at coin subscriber stations in the diallocal oilice. A feature of the invention is the use of a compositesignaling channel for controlling the operation of a coin controlselector in a dial local ofiice for establishing connection with aprepay coin subscribers station and the provision of signal meanscontrolled over this signaling channel by coin collect and coin refundbattery potentials for efiecting the collection or refund of coinsdeposited at subscriber stations.

A telephone system arranged in accordance with the invention and itsfeature is shown schematically in the drawing, in which Figs. 1 and 2represent a local dial oflice, Figs. 5 and 6 represent a toll office andFigs. 3 and 4 represent trunks between these oinces arranged forcomposite signaling. Fig. 7 shows the relative position in which Figs. 1to 6 are placed to form an operative arrangement.

The local dial oflice shown in Figs. 1 and 2 comprises a coinsubscribers station" I l and line l2, a line finder I l having access tothe line l2, a first selector 2d, a coin trunk circuit l8interconnecting the line finder and first selector circuits, tworecording completing trunk circuits OTI and GT2 connected to terminalsin the bank of the first selector, a coin control circuit CC and a coincontrol selector circuit CCS.

The subscriber station H is of the prepay coin box type comprising acoin control magnet, Ill for collecting and refunding deposited coins.The telephone set is of the common battery type and a dial (not shown)is provided for control ling the establishment of desired connections.The line finder and selector switches are of the step-by-step two-motiontype. The line finder M is represented bya set of brushes l5, [6, ii

and a single set of terminals it. The first selector 26 is representedby a set of brushes 2|, 22 and 23 and two sets of terminals 24 and 25.Reference may be had to Automatic Telephony by Smith and Campbell, 2ndedition, pages 53 to 65, for a description of the structure andoperation of step-by-step two-motion switches and their operation whenused as selectors. Reference may be had to Patent 1,799,654, grantedApril 7, 1931 to R. L. Stokely for a description of the operation of atwo-motion switch when used as a line finder. Reference may be had toPatent 1,569,623 granted January 12, 1926 to B. G. Dunham and Patent2,427,000 granted September 9, 1947 to. H. Hovland for disclosure ofcoin trunk circuits similar to coin trunk circuit 18.

The coin control circuit CC is adapted to receive dial and coin controlsignals over a composite signaling channel of trunks TI and T2 be tweenthe dial and toll oiiices. The coin control selector CCS has access to agroup of recording completing trunk circuits and is controlled by dialimpulses to select the particular one of these trunk circuits which isat that time connected to the coin station at which the disposal ofcoins is to be effected. The coin control signals thereafter received bythe coin control circuit CC are repeated to the recording trunk circuitto selectively efiect the collection or refund of coins as required. Theoperations of these circuits are hereinafter described in detail.

The toll oiiice, shown in Figs. 5 and 6 comprises two incoming trunkcircuits III and 1T2 and a coin control trunk circuit CCT, each arrangedfor signaling over a composite signaling channel of trunks TI and T2.The trunk circuits are jack-ended at an operator position Hi l which isequipped with a group of cords, an operator telephone set, and otherposition equipment including a dial for use in establishing callsoutgoing to dial oiiices. Reference may be had to Patent 1,675,956granted July 3, 1928 to L. F. Porter for complete disclosure of a tolloperators cord and position equipment. The operator position is alsoprovided with a coin control cord M5 for use with trunk circuit COT ineffecting the collection or refund of coins at any coin subscriberstation in the local dial oflice which is making a toll call. The trunkcircuits ITZ and CCT are shown, and hereinafter described, in detail.

The two two-wire trunks TI and T2 represent a group of similar trunksinterconnecting the toll and local dial oflices. Composite sets andrepeating coil equipment are connected at each end of the trunks TI andT2 to provide three two-way talking channels, three composite signalingchannels, and a ground potential compensating channel. One talkingchannel interconnects trunk circuits OTI and ITI and comprises repeatingcoils I08 and it and the conductors of trunk TI. Another talking channelcomprises repeating coils 8B and II and the conductors of trunk T2, thischannel being associated with trunk circuits (not shown) which do notrequire a separate signaling channel. The third talking channelinterconnects trunk circuits OTE and 1T2 and comprises phantom repeatingcoils 90 and I29 and the conductors of trunks TI and T2. One compositesignaling channel comprises the tip conductor of trunk TI and interconnects trunk circuits OTI and ITI. Another composite signaling channelcomprises the ring conductor of trunk TI and interconnects trunkcircuits 0T2 and 1T2. A third composite signaling channel comprises thetip conductor of trunk T2 and is used for coin control between coincontrol trunk circuit CCT in the toll oiiice and coin control circuit CCin the local dial ofiice.

While only one of the composite signaling channels over trunks TI and T2has been used for coin control, the arrangement may be modified eitherto provide, two or to provide three coin control signaling channelsbetween the toll oflice and the local dial ofiice.

A detailed description of the operation of the system shown in thedrawing will be preceded by a general outline of the operations involvedin toll calls from prepay coin subscriber stations.

Responsive to the removal of the receiver at a prepay coin subscribersstation II, a line finder I4 is operated to connect the associated coin'trunk circuit I3 to the subscribers line I2. The

coin trunk determines whether a coin has been deposited and, if so, dialtone is then transmitted to the station I I. Responsive to the dialingof an operator code, the first selector 2i! and auxiliary selectors ifnecessary (no auxiliary selector being shown), are selectively operatedto select an idle outgoing recording-completing trunk circuit, such as0T2, which is connected over a talking channel of trunks arranged forcomposite signaling to an incoming trunk circuit such as 1T2 terminatingat a position of the toll board. The aforementioned Hovland Patent2,427,000 describes the operations of line finder, coin trunk andselector circuits in connecting a prepay coin subscriber station to arecording-completing trunk circuit. A calling lamp is lighted at thetoll board and the call is answered by connecting an idle cord to theansweringjack of the incoming trunk circuit. It is assumed that the coinlines are in a separate line finder group and that a separate group oftrunks is provided for these lines to the toll board, and in this casethe trunk circuits are not arranged to transmit a class of servicesignal to the tolloperator. When the toll operator answers the call, thecalled oiiice code and number are received from the calling station andthe coin initially deposited is automatically returned and the operatorrequests the deposit of coins in payment for the call. After completionof the call, or as soon as the toll operator finds that the call cannotbe completed, the coin control cord I45 is connected to a coin controltrunk circuit CCT and the operator dials a particular number identifyingthe recording-completing trunk circuit used in connecting the coinsubscriber to the toll board. The dial impulses are transmitted over theassociated composite signaling channel of trunks TI and T2 to the coincontrol circuit CC in the local dial office; and these impulses arerepeated to operate the coin control selector CCS to establishconnection with the desired recording-completing trunk circuit. The tolloperator then operates the coin collect key or the coin refund key totransmit either a coin collect or a coin return signal over thecomposite signaling channel to the coin control circuit CC. In responseto this signal the recordingcompleting trunk circuit is controlled bythe coin control circuit CC to eflect the collection or refund of thecoin at the calling station, as required.

It is to be noted that, whereas in the arrangement shown in the drawingthe disposal of coins is effected by transmitting signals over acomposite signaling chann l to a recording-completing trunk circuit, ondelayed toll calls a switching trunk is employed by the operator inconnection with the local dial office; and selector and connectorswitches are operated to complete the connection with the callingstation. In such a case, the coin control selector CCS would beselectively controlled to select the switching trunk circuit in the dialoffice (instead of selecting a recording-completing trunk circult) toestablish a connection for controlling the disposal of coins at thesubscriber station.

Assume now that a call has been initiated at a prepay coin station Ii,that the line finder I4 operated to connect the line I2 to coin trunk.IB, that the coin trunk operated to prepare selector 2i for operationand that the terminal of relay back contacts of relay 13, right windingsof repeating coil as and a back contact of 'relay G2, and windings ofrelay 3! to the opposite poles of the central oihce battery. Relay 3! isthereby operatively energized. The operation of relay 3! closes acircuit including a back con tact of relay for operating theslow-to-release relay 33, and connects ground to conductor 29 to markthe trunk circuit busy and to hold the selector and line finder switches2t and I4 in operated position in usual and well-known manner. Theoperation of relay 33 closes a connection from the dial ofice ringinginterrupter through condenser 35% and back contacts of relays 36, 43 andas to conductor 28, thereby to transmit audible ringing tone to thecalling station to indicate that an operator is being signaled. Relay 33also connects ground to conductor 29. The aforementioned operation ofrelay 3| also closes a circuit for operating relay 32, this circuitincluding back contacts of relays M and M. The

, operation of relay 32 disconnects ground from,

, and conductor I22, to ground at a back contact I22, thence throughcoil I23, upper 5 of relay I35 intrunk circuit 1T2. Relay-I25 operatesand connects ground to conductor I2I to operate relay 34. The operationof relay I345 closes a circuit for lighting lamp I33 associated withanswering jack i363 and closes a circuit for operating relay Isl. When atoll operator inserts the plug I42 of a cord It?! into jack I38, thesleeve relay I35 is operated due to the energization of its lowerwinding in series with the sleeve conductors of jack Itil and plug M2 tobattery in the position circuit Hi4. The operation of relay I35 causesthe successive release of relays I34 and Isl. The release'of relay I34extinguishes the calling lamp I33, and the release of relay I3! closes acircuit for operating relay let. The operation of relay I35 opens theterminating bridge comprising resistor I38 and condenser I39 which isnormally connected across the talking conductors of trunk circuit TF2.The operation of relay I325 disconnects ground from, and connectsbattery to, conductor winding of relay I25, lower winding of coil H18,lower conductor of trunk Tl, lower winding of coil I9, up-

per and middle windings of relay 95 to ground. Relay $5 operates andconnects ground to conductor 9| to operate relay 35 of therecordingcornpleting trunk circuit T2. Relay 35 closes a holding circuitfor relay 33 independent of relay 3!, and closes an operating circuitfor relay 36. The operation of relay 35 opens the connection betweencondenser 34 and conductor 28, to terminate the transmission of ringingtone to the calling station; and closes a circuit, including a backcontact of each of relays 3i and 45, for operatively energizing the leftwinding of relay 30. Relay 30 operates, looks through its right winding,and interchanges the connections be tween the windings of relay 3! andconductors 21 and 28 so as to reverse the current in the bridge (notshown) across the outgoing talking conductors of coin trunk circuit I8,thereby effecting the closing of the talking connection between line I2and the answering operator in the manner described in the aforementionedHovland patent.

The recording-completing trunk circuit is arranged to automaticallyeffect the return of the coin initially deposited at station II inresponse to the answer of the toll operator. To this end, the operationof relay 3! closes a connection from the winding of relay S's through aback contact of relay 45, and a front contact of relay 3G to aninterrupter 38, the brush of this interrupter being connected to ground60' times per minute.

Relay 3] is thereby operated as soon after relay 353 operates asinterrupter 33 closes the ground connection. The operation of relay 31opens the operating circuit of relay 3t, and closes a circuit includinga front contact of relay 3%] and a back contact of relay 45 foroperating relay 39. Relay 39 looks through its continuity front contactto ground at a front contact of relay 30. As soon after relay 39operates as the interrupter ground connection is opened, relay 3!releases thereby effecting the operation of relay B. The operation ofrelay 40 closes a circuit for operatively energizing the upper windingof relay ii. Relay 4| opens the circuit for operating relay 3?, closes ashort circuit across retard coil it, and extends its operating ground tooperatively energize the upper Winding of relay 42.

,The operation of relay (l2 closes a holding circuit for relay 33,closes an operating circuit for relay 44, closes a locking circuitthrough the lower winding of relay ll, disconnects the lower winding ofrelay 3| from conductor 28, and extends its operating ground tooperatively energize the Winding of relay 4-3. The operation of relay 43completes a connection from coin return battery CRB, through frontcontacts of relays 39 and 46, front contacts of relay t! in parallel,front contacts of relay 43, front contacts of relay 42, front contactsof relay 38, conductors 2i and 28, selector brushes 2i and 22, throughthe coin trunk I8, line finder brushes I5 and H3 and the conductors ofline I2 to operate the coin magnet It at station II to return thedeposited coins. When relay 3'! reoperates due to the next connection ofground through interrupter 33, approximately half a second after itsprior release, ground is connected to short circuit the winding of relay39. ihe release of relay 39 disconnects the coin return batery CRB fromthe line l2 and closes a circuit for operating relay 45. Relay illremains operated until relay 3'! again releases so as to hold relays iI,t2 and 43 operated long enough after relay 39 releases to eifectdischarge of the line. Relay "l5 locks under control of relay 5%, andholds open the operating circuits of relays 39 and it. When relay 3?again releases approximately half a second after relay 39 released,relay 10 releases thereby deenergizing the upper windings of relays lland 42 and deenergizing the winding of relay &3. Relay A3 releases,thereby deenergizing the lower winding of relay 52; and the release ofrelay 42 causes the release of relays 44 and dl. With relay 43 released,the talking connection between the toll operator and calling station isagain closed. During the time relay ll was operated, relay 32 releasedto disconnect battery from conductor 92 and cause the release of relayI25 in the toll office; whereby ground is connected to the upper lowresistance winding of sleeve relay I35 of trunk circuit 1T2 to cause thelighting of the cord supervisory lamp I43 while the coin is beingreturned at the calling station.

The toll operator receives the called office name and called subscribernumber from the calling subscriber and informs the calling subscriber ofthe amount to be deposited in payment for the call. After the call iscompleted the operator proceeds to collect the coins; or, if the callcan not be completed, the coins are returned. In either case theoperator connects the plug I49 of a coin control cord I lb to the jack559 of an idle outgoing coin control trunk circuit GUI and then dialsthe number assigned to the record-- ing-completing trunk in the dialoffice. When plug I69 is connected to jack I55, relay I52 is operated ina circuit which includes the left contact of coin return key Ml, backcontacts of dial key I46, ring conductors of plug Hit and jack I50,winding of relay I52 and a back contact of relay I58. If the dial keyHit is already operated, the circuit for operating relay I52 ineludesfront contacts of key I -lG andthe impulse contacts of the dial. 'lheoperation of relay I52 closes a circuit for operating relay I53, thiscircuit including the front contact of relay I52, a back contact ofrelay I58, winding of relay i53, the sleeve conductors of jack I58 andplug I49 and contacts of keys Hi8 and I57. Relay I53 locks independentof relays 52 and 53 and closes circuitsfor operating relays I56 and 55.With both of relays Iild and I55 operated, a circuit is closed foroperating relay IE I. The operation of relay l5? closes a circuit forlighting busy lamp I 5I and closes a circuit for operating relay I58.The operation of relay I58 opens the operating circuit of relay I53.closes a locking circuit for relay I55 to ground at a front contact ofrelay I52, opens the operating circuit of relay I52, and closes acircuit for operating relay I59, the last-mentioned circuit includingthe up per front contact of relay I58, a front contact of relay I57,winding of relay I55, and tip conductors of jack I55 and plug I45. RelayI55 locks independent of relays I? and I55, closes a circuit formaintaining the energization of busy lamp I5I independent of relay I5'I,and connects the winding of relay I55 in series with the winding ofrelay I52 so as to reoperate relay I52 and operate relay I65. Normallythe outgoing signaling conductor H2 is connected through coil H3, and aback contact of relay I59 to ground at a back contact of relay I55. Withboth of relays I59 and I55 operated, ground is disconnected fromconductor H2 and a circuit is closed from battery I54 through the frontcontact of relay I60, resistors I5I and a front contact of relay I54, afront contact of relay I 55, a front con tact of relay I55, coil H5,conductor IIZ, upper winding of coil H5, upper conductor of trunk T2,upper winding of coil 89 and through the upper windings of compositesignaling relays 85 and 54 to ground. Relay 55 operates but relay 84 ismarginal and does not operate at this time. The operation of relay 55disconnects ground from conductor 52 and connects ground to conductor 8|to operate relay 5! of coin control selector CCS. The circuit foroperating relay 5! is traced from conductor SI, through a back con tactof each of relays 52, 53, 5| and 54 of coin control circuit CC,conductor 58, a back contact of each of relays 5?, 55 and 68, winding ofrelay BI conductor 57, a back contact of relay 55 and through resistor55 to battery. The operation of relay 5| closes a circuit for operatingslow-torelease relay 52, thereby preparing selector CCS for operationresponsive to dial impulses transmitted over the coin control signalingchannel from the toll ofiice.

When the toll operator dials the digits identifying therecording-completing trunk circuit 0T2 in the dial office, the dialingloop is alternately opened and closed by the impulse contacts of thedial to effect the alternate release and reoperation of relay I65. Eachtime relay I50 releases the signaling conductor [I2 is transferred frombattery I 54 to ground, causing the release of relay 85 in the dialoffice; and each time relay I50 reoperates, ground is disconnected fromand battery I64 is reconnected to signaling conductor I I2,

causing the reoperation of relay 85 in the local dial ofiice; Relay 85is thus operated to repeat the dial impulses incoming over the signalingchannel from the toll ofiice to relay SI of the coin control selectorcircuit. The release of relay 6|, responsive to the first dial impulse,closes a circuit from ground through the back contact of relay 6|, upperfront contact of relay 62, lower normally closed contact of the verticaloff-normal spring VON, winding of relay 53 and Winding of verticalstepping magnet VM. Relay 63 and the stepping magnet VM both operate.The operation of the stepping magnet raises the brushes one step. TheVON springs are actuated when the shaft and brushes are moved out ofnormal position. When relay 6i reoperates at the end of first dialimpulse, stepping magnet VM releases. Relay 6| releases and reoperatesresponsive to each succeeding dial impulse in a digit train, therebycausing the operation of the stepping magnet VM responsive to each dialimpulse of the first digit train of impulses. Relay 63 is slow toreleasegand remains operated until all of the impulses in the train havebeen received. The circuit for reoperating the stepping magnet VM andreenergizing the winding of relay 63 responsive to the second andsucceeding impulses of a digit train includes a front contact of the VONsprings and the front contact of relay 63 instead of a back contact ofthe VON springs as in the case of the first impulse of the train. Relay62 is also slow in releasing and remains operated during the response ofrelay 5i to dial impulses. Each operation of stepping magnet VM raisesthe brushes one step, thereby selecting a level of the bankcorresponding to the first digit dialed by the toll'operator. During theinterval between the first and second digit trains of dial impulses,relay 63 releases thereby transferring the operating ground connectionfrom the winding of relay 63 and magnet VM to the winding of relay 65and rotary stepping magnet RM. Thus the alternate release andreoperation of relay 5! responsive to the second digit impulse traincauses the operation of relay 65 and successive operations of steppingmagnet RM whereby the brushes are rotated in the selected level intoengagement with the terminal set corresponding to the second digitdialed. When the brushes move out of the normal rotary positionresponsive to the first impulse of the second digit, the rotaryoff-normal springs RON are actuated; and the operating circuit forreenergizing relay 65 and reoperating stepping magnet RM responsive tothe second and succeeding impulses of the second digit train includesthe front contact of relay 65, relay 65 being slow in releasing so as toremain operated while relay BI is responding to these impulses. Whenrelay 65 releases after all of the impulses of the second digit trainhave been received, it connects the lower winding of relay'G'l in acircuit through the front contact of springs RON in series with thestepping magnet RM. Relay 61 operates but the rotary stepping magnet ismarginal and does not reoperate in this circuit. The operation of relayS'Icloses a circuit for energizing the lower winding of relay 64 andopens the normally closed short circuit across the winding of relay andthe upper winding of relay I34 whereby these windings are connected inseries with the winding of relay BI and conductors 5! and 58. Relayoperates but relay 54 is not operated because the energization of onewinding opposes that of the other winding. The operation of relay 55closes a holding circuit for relay 62 independent of relay 6|. Theterminals selected responsive .to the first and second digit trains ofdial impulses are connected by conductors ll, 48 and 49 to therecording-completing trunk circuit 0T2.

If the operator wishes to collect the coins at station II, the coincollect key I48 is operated causing the release of relay I53 of the coincon trol trunk circuit CCT. The release of relay I53 causes the releaseof relay I54; but relay I55 remains operated, being locked under controlof relays I58 and I52. The release of relay I54 closes another holdingcircuit for relay I55 to ground at a front contact of relay I55 andcauses the successive release of relays I5l, I58 and IE5. The release ofrelay I54 also disconnects battery I64 from, and connects battery I55to, the signaling conductor H2, Thebattery I 55 is poled in the samedirection as battery I54 but is a higher voltage battery so as to causethe operation of r 9 marginal relay 84 in the dial office, withoutreleasing relay 85. When the operator restores the collect key I49,relay I53 reoperates and the reoperation of relay I59 causes thereoperation of relay I54, whereby signaling conductor H2 is disconnectedfrom battery I55 and is connected to ground at the back contact of relayI50. The reoperation of relay I55 causes the successive reoperation ofrelays 15?, I58 and W; and, when relay I59 reoperates, ground isdisconnected from, and battery I65 is again connected to, signalingconductor H2. The aforementioned operation of relay 84 connects ou d toc u t r 83 er ating relay 53 of the coin control circuit CC. Theoperation of relay 53 closes a circuit for operating relay 54, thiscircuit including a front contact of relay 53, a back contact of relay52, conductor 8| and the front contact of relay B5. The operation ofrelay 59 closes a circuit for operating relay and reverses the currentthrough conductors 51 and 59, thereby to cause the release of relays 60and SI and the operation of relay 5 in the coin control selector circuitCOS. The operation of relay 5! causes the operation of relay 52, and theoperation of relay 52 causes the release of relay 54. When relay 54releases, conductor 51 is reconnected to battery through resistor 55 andconductor 58 is connected through the high resistance 56 to ground at afront contact of each one of relays 53, 52 and EI as long as the relayremains operated. The current in the loop circuit through conductors 52and 58 is reduced by the high resistance of resistor element 55 to causethe reoperation of relay 5% without causing the reoperation of relay BIand without causing the release of relay 64. The aforementioned releaseof relay 55 causes the release of relay 5|. Relays 5| and 52 are slow torelease to insure the operation of relay 59 in the coin control selectorCCS. The release of relay 5! opens the operating circuit of relay 52,but relay 52 remains operated under the control of relay 55. Theaforementioned reoperation of relay 69 in the coin control selectorprevents the release of relay 62, and therelease of relay 5! closes acircuit including the outer upper contact of relay 5'! and both windingsof relay 55 in series, for operating relay 55. Relay 55 looks throughits upper winding and front contact, through a back contact of relay 59to ground at a front contact of relay 62, opens its own operatingcircuit, conneets the 60 impulse per minute interrupter 38 to the upperwinding of relay 51, and closes a circuit for operating relay 58.

52 and 6|, opens the operating circuit of relay 6?, closes a circuit forholding relay 54 operated, and closes a connection from ground at thefront contact of relay 65, through the inner lower front contact ofrelay 53, middle brush and engaged terminal of the coin controlselector, and conductor 48 to operatively energize the upper winding ofrelay 4| of the recording-completing trunk circuit 0T2. The operation ofrelay 4! causes the operation of relays 542, .43 and 5 4 as hereinbeforedescribed and closes a connection from the low tone source TNI in thecoin control selector circuit CCS, through a front contact of relay 54,a front contact of relay 59,, tone condenser TNC, and bottom brush ofselector CCS, conductor 49, a front contact of relay AI to the upperwinding of repeating coil 99, thereby transmitting a tone over thephantom circuit of trunks TI and T2 through repeating coil 129, trunkcircuit 1T2 and cord I50 to the toll operator to Relay 58 looks throughits upper winding under control of relays indicate that the coin collectcircuit is being closed. After relay 68 opens the operating circuit ofrelay (il relay 5? is held operated by its upper winding as long as theground connection through interrupter 38 is closed. When relay 5!releases, the winding of relay 59 is connected to the interrupter; and,as soon as the ground connection is again closed through interrupter 38,relay 59 operates. The operation of relay 59 cioses a circuit foreffecting the operation of the coin magnet at the subscriber station I Ito collect the coins, this circuit being traced from coin collectbattery CCB in the coin control selector circuit 008, through a frontcontact of relay 6'5, winding of relay c9 front contact of relay 59, topbrush of selector CC S and engaged terminal, conductor ill, a backcontact of relay 59, front contacts of relay ii, front contacts of relay49, front contacts of relay 52, contacts of relay 30, ccnductcrs 2i and2.9, brushes 2I and 22 of selector 20, through coin trunk circuit 13,brushes I5 and is of line finder I l, conductors of line if, and throughthe winding of coin magnet III to ground; whereby the coin magnet I0 isoperated to collect the deposited coins. The coin collect current alsoeffects the operation of relay 59 in the coin control selector circuitand relay 5 5 closes a circuit for holding relay operated.

As soon as interrupter 38 opens the connection to ground, relay 59releases. The release of relay 55 opens the circuit through relay 69,and relay 59 releases; but relay 55 is held operated through the backcontact of relay 59. The next closure of the ground connection byinterrupter 38 causes the reoperation of relay 59. If the coins werecollected at the calling station by the first closure of the coincollect circuit, relay 59 is not reoperated and relay 55 releases. Therelease of relay 55 causes the release of relay 59 and opens theoperating circuit of relay 58; but relay 65 is held operated as long asrelay 65 is operated and relay 5-! is released. When the coin collectkey I48 is restored to normal, the above-described disconnection ofbattery I65 from, and reconnection of battery 54 to, conductor H2 causesthe release of relays 84 and 53 in succession. The release of relay 53causes the release of relay 5-2, whereby conductor 58 is a in connectedto ground at the front contact of relay 35; so that relay IiIreoperates, thereby causing the release of relay 58. When relay 58releases, the tone source TN! is disconnected from conductor 59 toterminate the transmission of tone through repeating coils 95 and I 25to the toll operator. The operator now removes the plug I{l9 from jackI59 causing the release of all relays in coin control trunk cir- .cuitCOT, whereby ground is again connected through resistors ifil and W3 andcoil I it to conductor I52 to cause the release of composite signalingrelay 85 in the dial ofiice. The release .of relay 85 causes the releaseof relays 59 and S -I in the coin control selector circuit, followed :bythe release of relays 52, 55 and 65. With relays -BI and 52 released,the release magnet BLS is operated to restore the shaft and brushes tonormal and springs RON and VON are also restored to normal, all in usualand well-known manner. The aforementioned release of relay 55 alsodisconnects ground from conductor 59, thus causing the successiverelease of relays 53 and 92 followed by the release of relays 45 and Min the recording-completing trunk circuit 0T2.

When the call is completed and the calling subscriber replaces thereceiver on the receiver ll hook, relay 3I releases followed by therelease of relay 32. The release of relay 32 disconnects signalingbattery from and connects ground to conductor 92 thereby causing therelease of the composite signaling relay I in the toll oifice. Therelease of relay I25 disconnects ground from conductor I2! and connectsground to the low-resistance, upper winding of relay I35 to effect thelighting of the cord supervisory lamp I43 as a disconnect signal' Whenthe toll operator disconnects cord I45 from jack I30, relays I35 and I36release in succession. The release of relay I36 disconnects signalingbattery from, and reconnects ground to, conductor I22 to cause therelease of composite signaling relay 95 in the dial oflice. The releaseof relay 95 causes the successive release of relays 35, 36 and 33,whereby trunk circuit 0T2 is restored to normal and ground isdisconnected from conductor 29 to release the selector and line finderswitches and restore all associated apparatus to normal.

If the call cannot be completed after coins have been deposited atstation II responsive to the toll operators request, the operatorreturns the coins by connecting the coin control cord I45 to jack I50,the dialing of the number of the recording-completing trunk 0T2, and theoperation of the coin return key I41. The operation of trunk circuitCCT, coin control circuit CC and coin control selector circuit CCS toconnect with the trunk circuit 0T2 are the same as above-described. Whenthe coin return key I41 is operated, ielays I53, I52 and I60 arereleased. The release of relay I60 disconnects battery I64 fromsignaling conductor H2 and connects ground through resistors I6I and I63and front contacts of relays I54, I and I59 to conductor I I2 to causethe release of composite signaling relay 85. The release of relay I53opens the operating circuits of relays I54 and I55 and the release ofrelay I52 opens the locking circuit of relay I 55. Relay I55 releasesbut relay I54 is slow in releasing and the release of relay I55 closes acircuit through its lower back contact for holding relay I54 operatedunder the control of relay I59. The release of relay I55 disconnectsground from signaling conductor H2 and connects battery I66 to conductorI I2 and causes the successive release of relays I51, I58 and I55.Battery I65 is of high enough voltage to cause the operation of marginalrelay 84 in the dial ofiice and is of opposite polarity to that ofbatteries I64 and I65 so as to be ineffective to cause 'the operation ofrelay 85. Relays I51 and I58 are slow in releasing to insure theconnection of battery I66 to conductor II2 for an interval sufiicientfor the operation of relay 84. When key I41 is restored to normal,relays I53 and I52 reoperate. The reoperation of relay I53 causes thereoperation of relays I55, I51, I58 and I50. The reoperation of relayI55 reconnects conductor II2 to ground through resistors I63 and I6I,thereby causing the release of relay 84; and

the reoperation of relay I again connects battery I 64 to conductor II2,causing the reoperation of relay 85 without reoperating relay 84.

In the dial office, the aforementioned release of relay 85 disconnectsground from conductor 8| thereby causing the release of relays 60 and6|; and the subsequent operation of relay 84 causes the operation ofrelay 53. Relay 53 connects ground through high resistance element 56 toconductor 53, and connects the winding of relay 52 to ground at the backcontact of relay 85. Re-

lay 52 locks under control of relay 53, connects ground to resistor 56,and disconnects the winding of relay 54 from conductor 8I. When relayreoperates and relay 84 releases due to the aforementioned disconnectionof battery I56 from and reconnection of battery I64 to conductor H2 atthe time the coin return key is released, relay 53 releases, followed bythe release of relay 52. With relays 52 and 53 normal, ground is againconnected from the front contact of relay 85 through conductor 8| andback contacts of relays 52, 53, 5I and 54 to conductor 53. During thetime the high resistance element 55 is connected in series withconductor 53, relay 66 is reoperated without reoperating relay 6! andwithout operating relay 64 of the coin control selector circuit. Withrelay 60 operated, relay 62 is operated; and, with relay 6| normal,relay 56 operates and locks, relay 68 operates and locks, and relays 4|,42, 43 and 44 of trunk circuit 0T2 are operated as hereinbeforedescribed. When relay 59 operates and since relay 54 is not operated,the coin return battery CRB is connected through a back contact of relay64, winding of relay 59, a front contact of relay 53, top brush ofselector COS, conductor 41, a back contact of relay 4!), front contactsof relays 4|, 43 and 42, contacts of relay 30 and conductors 21 and 28,through selector 20, coin trunk circuit I8, line finder I4 and line I2to the coin magnet I 0 of station II; and the high tone source TN2 isconnected through the inner lower back contact of relay 64, a frontcontact of relay 68, condenser TNC, bottom brush of selector CCS,conductor 49 and a "front contact of relay 4| to repeating coil 98 totransmit tone to the toll operator to indicate that coin return batteryis being applied to return the coins deposited at station II. As soon asinterrupter 38 opens the connection to ground, relay 53 releases. Therelease of relay 59 opens the circuit through relay 53; and relay 69releases; but relay 55 is held operated through the back contact ofrelay 53. The next closure of the ground connection by interrupter 38causes the reoperation of relay 58. If the coins were returned by thefirst closure of the coin return circuit, relay 63 is not reoperated andrelay 66 releases. The release of relay 66 causes the release of relay5%. When relays 53 and '52 release,

-: due to the release of relay 84 and reoperation of relay 85 resultingfrom the release of the coin return key I41 as above described, relay BIreoperates and relay 68 releases, thereby terminating the transmissionof tone from source TN 2 to the toll operator and disconnecting groundfrom conductor 43 to cause the successive release of relays 43, 42 and4I. When the coin control cord I45 is disconnected from jack I50 thecoin control trunk circuit CCT, coin control circuit CC, and coincontrol selector circuit are restored to normal in the mannerhereinbefore described.

What is claimed is:

1. In a telephone system, a dial central ofiice comprising subscriberslines, coin stations of the prepayment type connected to some of saidlines, another oifice including an operator position, trunks betweensaid ofiices arranged to provide a plurality of talking channels and aplurality of composite signaling channels between said ofiices, trunkcircuits in said dial office, one for each of said talking channels,means comprising one of said talking channels and the associated one ofsaid trunk circuits connecting said position to one of said coin lines,a coin control cord at said position, a switch in said dial ofliceindividual to one of said composite signaling channels, said switchhaving access to said trunk circuits, means comprising a dial associatedwith said cord and comprising said one signaling channel for operatingsaid switch to connect with said one of the trunk circuits, coin controlpotential sources associated with said switch, means associated withsaid one of the composite signaling channels and controlled by the coincollect and coin return keys of said cord for selectively transmittingcoin control signals over said one signaling channel, and means in saiddial oflice controlled by said coin control signals for effecting theconection of the desired one of said coin control potential sources tosaid one trunk circuit to cause the collection or the return of coinsdeposited at the coin station of said coin line as desired.

2. In a telephone system, a central office including a subscribers lineand station of the prepayment coin type, a trunk circuit, an operatorposition including a dial, means including said trunk circuit connectingsaid station to said position, a trunk between said position and centraloffice arranged for composite signaling, a coin control cord at saidposition and coin control keys associated with said cord, a coin controlselector in said central office having access to said trunk circuit,means including said dial and coin control cord and a compositesignaling channel of said trunk for selectively operating said selectorto connect with said trunk circuit, potential sources in said centraloffice, one for effecting the collection and another for effecting thereturn of coins deposited at a coin station, and means associated withsaid selector and trunk circuits and controlled by said coin controlkeys over said composite signaling channel for selectively effecting theconnection of the desired one of said potential sources to said coinsubscribers line.

3. In a telephone system, a central office including a subscribers lineand stations of the prepayment coin type, an operator position includinga dial and a coin control cord and associated coin control keys, a trunkbetween said position and central oflice, said trunk being arranged forcomposite signaling thereover, a coin control selector in said centraloffice, signal receiving means associated with said selector andarranged to receive selective and coin control signals over a compositesignaling channel of said trunk, a coin control trunk circuit connectedto the other end of said channel, means in said trunk circuit controlledby said dial for transmitting dial impulses over said channel to operatesaid selector to establish connection with said subscribers line,potential sources associated with said selector, one for effecting thecollection and another for effecting the return of coins at saidsubscriber's station, and means in said trunk circuit selectivereceivingmeans to connect the desired one of said potential sources to saidsubscribers line.

4. In a telephone system comprising a central office includingsubscriber lines and stations of the prepayment coin type, an operatorposition, a trunk between said position and central ofiice, meansconnected to said trunk providinga com- :posite signaling channel overone of the conductors of the trunk, a dial, a coin control cord and coincontrol keys at said position, a coin control selector in said centraloflice for use in effecting the collection or return of coins depositedat a coin station, signal receiving means in said central officeconnected to said composite signaling channel of said trunk forcontrolling the operation of said selector, and signal transmittingmeans controlled by said cord, dial and keys for transmitting dialimpulses and coin control signals over said signaling channel to saidsignal receiving means to selectively control the operation of saidselector to establish connection with a desired subscriber line andeffect the collection or refund of coins deposited at the subscriberstation as desired.

5. In a telephone system comprising a central oifice includingsubscriber lines and stations of the prepayment coin type, an operatorposition including a dial, a coin control cord and com control keys, atrunk between said position and central office, means connected "to saidtrunk providing a composite signaling channel over one of the conductorsof the trunk, signal receiving means in said central office arranged toreceive selective and coin control signals over said composite signalingchannel of said trunk, said signal receiving means including a polarizedcomposite signaling relay and a non-polarized marginal relay connectedin series to a conductor of said trunk, a coin control trunk circuitconnected to the other end of said signaling channel including meansresponsive to the connection of said cord with said trunk circuit foreffecting the operation of said polarized composite signaling relay,means controlled by said dial for effecting the alternate release andreoperation of said p0- larized composite signaling relay responsive todial impulses, means controlled by one of said coin control keys foreflecting the operation of said marginal relay while maintaining theoperation of said polarized relay, and means controlled by the other ofsaid control keys for efiecting the operation of said marginal relay andthe release of said polarized relay.

FREDERICK R. LAMBERTY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,226,730 Lomax Dec. 31, 19402,385,720 Molnar Sept. 25, 1945 2,471,087 Anderson May 24, 1949

